Human papillomavirus type 6, HPV 6, is one of the major causes of the sexually transmitted disease, condyloma acuminata. HPV 6 DNA is also found in vulvar and cervical carcinomas. The long term objective of this proposal is to elucidate the molecular basis of HPV 6 pathogenicity. The target cell for HPV 6 is the keratinocyte. The extent of gene expression of HPV 6 depends on the state of differentiation of the keratinocyte. However no in vitro system which produces HPV 6 virions is available. In this proposal, quantities of HPV 6 proteins or peptides will be produced. In some cases, HPV 6 open reading frames will be inserted into expression vectors and the proteins will then be expressed in E. coli. Alternatively, some HPV 6 putative peptides will be chemically synthesized. Rabbits will be immunized with these proteins/peptides. The resultant antisera will then be used a) to probe tissue sections from benign and malignant lesions known to contain HPV 6 for expression of protein in different layers, using the avidin-biotin complex method, and b) to characterize HPV 6 proteins extracted from such lesions. In addition, the HPV proteins/peptides will be used to determine to which proteins patients make antibodies. This will be important information for epidemiological studies. In a second and interrelated branch of the proposal, HPV 6-related variants, that is DNA which, on a dot blot, hybridizes to prototype HPV 6b DNA, will be cloned into bacteriophage lambda. These variants will include HPV 6 subtypes and new types which contain some sequences common to HPV 6. Restriction maps of these variants will be constructed and compared to the prototype HPV 6b genome in order to locate the sites of the variation on the genetic map. The maps of variants of HPV 6 isolated from benign and from malignant lesions will be compared. These analyses will a) clarify the relationship of subtypes and types, b) determine whether there is a significant correlation between the location of variation and the type of lesion from which the DNA was isolated and c) determine the extent and location of variability within a type. These latter data are important in the consideration of future vaccine development.